Synthetic resins are known to form strong adhesive bonds with many materials. In fact, it is these strong adhesive properties which have made one such polymer system, the epoxies, generally a matrix material of choice for forming fiber reinforced composites. However, fiber reinforced epoxy resin composite materials lose their elevated temperature mechanical properties, and in some instances, their room temperature mechanical properties on exposure to natural conditions such as heat, sunlight, and moisture over time periods ranging from a few months to several years. This is true even for composites containing not only popular and well known commercially available epoxies, but even to some extent, for composites containing conventional polyesters, polysulfones and polyimides as well. And while there are many patents directed to polyimide resin materials, very little attention has been directed to their specific functionality and its effect on improving the properties for which these resin compositions have their most popular use. Note for example, U.S. Pat. Nos. 3,380,964; 3,406,148; 3,450,711; 3,678,073; 3,717,615; 3,759,779; 3,761,430; 4,011,386; and 4,043,986.